Bulldozer moldboard corner bit



April 17, 1962 M. RAKISITS 3,029,534

BULLDOZER MOLDBOARD CORNER BIT Filed May 23, 1960 IN V EN TOR. k%z c%zeZ-%2% z's 2'55. J4

United States Patent 3,029,534 BULLDOZER MOLDBOARD CORNER BIT MichaelRakisits, 2700 Pine Ridge Lane, La Crescenta, Calif. Filed May 23, 1960,Ser. No. 30,925 1 Claim. (Cl. 37-141) This invention relates to earthmoving apparatus and more particularly to an improvement in thereplaceable corner bits for the moldboards of bulldozers.

The corners of bulldozer blades (commonly called moldboards) arecustomarily supplied with replaceable bits to absorb the wear andabrasion incident to use. When the cutting edge of the bits is wornaway, the bit must be scrapped and replaced. The bits currentlyavailable for such use have an insufficient amount of metal for thesacrificial cutting edge portion thereof with the result that they aresubject to frequent replacement at very considerable expense.

Having this situation in mind, the principal objects of the presentinvention are to provide a replaceable corner portion or hit forbulldozer moldboards characterized by certain novel configurations whichpresent additional cutting edge metal for sacrificial wearing, which areso anchored to the moldboard as to be capable of withstanding servicestresses, which are simple in construction and economical tomanufacture, and which are readily installed and removed incident toreplacement when they are worn out.

With the above objects in view, together with such the. front end of thetractor or bulldozer and raised and lowered by the usual power means(not shown) attached additional objects and advantages as maysubsequently invention, reference being had to the accompanying drawingswhich form a part of said specification and in which:

FIG. 1 is a front elevational view of a bulldozer moldboard showing thecorner bits comprising one embodiment of the invention attached thereto,the center portion of the moldboard being broken away to conserve space,

FIG. 2 is a side elevational view of the left hand side of FIG. 1,

FIG. 3 is an enlarged, front prospective view of the left hand cornerbit shown in FIG. 1,

FIG. 4 is an enlarged, fragmentary, side elevational view of the lower,left hand side portion of FIG. 1, a portion of the moldboard beingbroken away to illustrate the configuration thereof otherwise concealed,

FIG. 5 is an enlarged, fragmentary, sectional View taken on the line 5-5of FIG. 1,

FIG. 6 is a further enlarged, sectional view taken on the line 66 of HG.1,

FIG. 7 is a prospective view of the components of the first form ofcorner bit and mounting means shown in the preceding figures,

FIG. 8 is a front elevational view of the corner of a bulldozermoldboard showing a second embodiment of the invention as initiallymounted thereon,

FIG. 9v is a sectional view taken on the line 99 of FIG. 8,

FIG. 10 is a view similar to FIG. 8 but showing the said secondembodiment of corner bit mounted on the moldboard by means of an adaptorto make more of the bit available for use, and

FIG. 11 is a sectional view taken on the line 11-11 of FIG. 10.

Referring first to FIGS. 1 through 7, there is shown a bulldozermoldboard M supported on the ends of upper and lower bars B and B bywhich it is mounted on to the said bars. The moldboard is formed fromheavy steel and is concavely curved as viewed from the front and isreinforced by side ribs R and R formed integrah 1y therewith. The rearface of the moldboard is also provided with suitable bosses forattachment of the bars B and B. Along the lower edge of the moldboardand extending between points inwardly of the side edges of the moldboardis a replaceable share S formed of hardened steel which is detachablysecured to the moldboard by bolts S extending through the moldboard asbest shown in FIG. 5.

The present invention comprises a mounting bracket component 1hereinafter referred to as the adaptor, and the replaceable bitcomponent 2. As will be apparent from FIG. 1, they are commonly providedin right hand and left hand sets for the opposite lower corners of themoldboard. Since, except for the reversal of the end portions thereof,the sets are identical, a description of the left hand set will servefor both and for that reason the same numbers will be applied to thecorresponding portions of the right hand set. The adaptor 1 comprises aflat base portion 3 secured to the lower front face of the moldboard bya series of countersunk head bolts 4 seated in a horizontal row ofcomplementary holes 4' in the adaptor'and thence through holes 4" in themoldboard and engaged by nuts 5 on .the rear face of the moldboard. Theadaptor extends from a point slightly outside of the adjacent side edgeof the moldboard to the adjacent end of the share S. Forwardly of thebolts 4, the under face of the adaptor extends at an acute divergentangle with respect to the moldboard surface forming a sloping underfaceportion 6.

y Toward the forward or lower edge thereof, the adaptor is provided witha second horizontal row of countersunk, bolt receiving holes 7 extendingthrough the face portion 6. The bit component 2 is of equal length tothe adaptor and is provided with a sloping topv surface 8 which iscomplementary to the sloping surface 6 of the adaptor and with a bottomsurface 9 which engages the 7 front face of the moldboard, wherefore, itfits in the space provided by the divergence of the adaptor face 6 andthe moldboard. This portion of the bit is provided With a row of holes10 which are aligned with the holes 7 in the adaptor and withcorresponding holes 11 in the moldboard. A series of countersunk headbolts 12 is disposed in the holes 7 and thence extend through thecomplementary holes 10 and 11 and are engaged by nuts 13 at the rearface of the moldboard and are thereby effective to clamp the taperededge 14 of the bit tightly between the spaced, opposed faces of theadaptor and moldboard. By this arrangement, the forces acting on the bitcomponent incident to use subject the bolts 12 to both tension and shearstresses whereby they are bet ter able to hold the bit tightly clampedagainst the moldboard.

The lower edge 15 of the bit protrudes beyond the lower edge of theshare and the outer side edge extends laterally beyond the side edge ofthe moldboard to the same extent as the adaptor. The side portion whichthus extends beyond the side of the moldboard and beyond the lower edgeof the moldboard provide the metal which is intended to be lost throughabrasion in use. Both to strengthen the bit and adaptor and to providestill additional metal which may be thus abraded with increased life ofthe bit, the bit and adaptor are provided with a forwardly projectingrib 16 which begins on the outer side edge of the adaptor and whichcontinues along the corresponding side edge of the bit thence forming arounded point 17 on the lower corner of the bit and thence continuessloping and tapering back to Patented Apr. 17, 1962 the plane of thelower edge of the bit at about the midlength of the bit. .By this means,the most metal (hardened steel) is provided at the point subjected tothe greatest wear.

FIGS. 8 through 11 illustrate another embodiment of the invention which,while not adapted for as rugged service as the first described form,possesses the advantage of being cheaper to manufacture and thereforeprovides a bit which is desirable in those uses involving less ruggedservice. In this form of the invention, the corner bit 18 comprises ablock of hardened steel which is generally rectangular in plan and whichis bent to the curvature of the front face of the rnoldboard. Along itsupper edge, it is provided with a series of equally spaced countersunkholes 19 in which the tapered heads of a series of bolts 20 arereceived. The bolts extend through a corresponding series of holes 21through the rnoldboard near the lower edge thereof and are engaged bynuts 22 at the back of the moldboard to clamp the bit to the cornerthereof as shown in FIGS. 8 and 9. When, however, the forward edge ofthe bit has been worn back to some point as, for example, thatrepresented by the line X-X in FIG. 9, the bit is removed from thernoldboard and an adaptor plate 23 is clamped on the rnoldboard by thebolts 20 and nuts 22, the heads of the bolts engaging countersunk holes23 in the adaptor plate which mate with the holes 21 in the rnoldboard.The adaptor extends beyond the lower .edge of the moldboard and carriesa second row of countersunk holes 24 which are parallel to the holes 19and which are disposed beyond the edge of the 'moldboard a distancewhich is equal to the distance of the rear edge of the bit from theholes 19 thereof. A second series of bolts 25 extends through the holes24 and 19 and are engaged by the nuts 26 to clamp the bit to the underside of the adaptor plate 23 with the edge of the bit abutting the loweredge of the moldboard and with additional metal of the bit thus madeavailable to increase the useful life of the bit. It will further benoted that additional manufacturing economies are achieved in thissecond form of the invention by reason of the fact that the lack of thereinforcing corner rib makes it possible for the same bit to be used ateither the right or left hand corner of the blade.

While in the foregoing specification, there have been described, certainpresently preferred embodiments of the invention, it will be understoodthat such disclosure has been by way of example, wherefore, theinvention is not to be deemed to be limited to the specific details ofsuch disclosure and, accordingly, it will be understood that theinvention includes as well, all such changes and modification in theparts, and in the construction, combination and arrangement of parts asshall come within the purview of the appended claim.

I claim:

In combination with a bulldozer rnoldboard a replaceable bit meanscomprising, an adaptor component and a bit component, said adaptorcomponent having a horizontally aligned series of holes extendingtherethrough adjacent the upper edge thereof and the rnoldboard having aseries of complementary holes extending therethrough and positioned tolocate said adaptor upwardly of a lower corner of the rnoldboard bybolts extending through said holes in said adaptor and said moldboard,said adaptor at the lower edge thereof having a downwardly extendingunder surface diverging from the plane of the front face of thernoldboard toward the lower edge of said adaptor, and said bit componenthaving an earth engaging edge disposed beyond the lower edge of thernoldboard and at the upper edge thereof having front and back faceportions complementary to said diverging faces of the rnoldboard andunderlying said diverging face of said adaptor, a series of horizontallyaligned holes extending through said adaptor, the underlying portion ofsaid bit and the rnoldboard, and a series of bolts extending throughsaid last named series of holes, effective to clamp the upper edge ofsaid bit between said adaptor component and the rnoldboard saidengagement between the faces of said adaptor and said bit which divergefrom the rnoldboard being effective to cause the bolts extending throughsaid last named series of holes to be subjeccted to tension by thestresses imposed on said bit incident to use.

References Cited in the file of this patent UNITED STATES PATENTS,732,639 Lillengreen Jan. 31, 1956 2,840,934 Hazzard et al. July 1, 19582,914,868 Launder Dec. 1, 1959 FOREIGN PATENTS 88,474 Norway Feb. 24,1954 1,117,289 France May 22, 1956

